The early stages of many neurodegenerative diseases are characterized by neurite damage and compromised synaptic function. Neurite degeneration often leads to neuronal cell death and can impair the conduction of signals in the affected nerves, causing impairment in sensation, movement, cognition, or other functions depending on which nerves are involved. Neurite degeneration is also a pathological hallmark of multiple sclerosis (“MS”). MS is an autoimmune, neurodegenerative disease that affects about 350,000 people in the United States and is a major cause of nervous system disability or death in young adults. A common clinical condition in humans afflicted with MS is the degenerative formation of neural lesions resulting from extensive degradation of the myelin sheaths surrounding the axons of the neurons, and eventual degradation of the axons themselves. The demyelination that occurs in MS is believed to be initiated by the attack of protease enzymes on three major neurological proteins: myelin basic protein (MBP), proteo-lipid protein (PLP) and myelin oligodendrocyte glycoprotein (MOG). Mechanistically, MS is an inflammatory demyelinating disease that is at least partially caused by an autoimmune response to myelin degradation products. Recent studies have emphasized the role of neurite and axonal injury in addition to the well known demyelation and inflammatory mechanisms.
Patients typically are diagnosed as having a neurite degenerative disease based on a combination of patient history and neurologic examination, including magnetic resonance imaging (MRI) of the brain and spinal cord, electrodiagnostic procedures (e.g., evoked potential tests such as visual evoked potentials, brain stem auditory evoked potentials, or somatosensory evoked potentials), and lumbar puncture to look for evidence of immunoglobulin synthesis in the cerebrospinal fluid.
Currently, there is no cure for diseases associated with neurite degeneration, so treatment typically involves management of symptoms and treatment of the frequency and severity of relapses.